The mystery of the disappearing Taskbar.

Once in a while, Windows gets into a terrible state and the Taskbar and its Start menu disappear. This is because the software that manages these, called the Windows Explorer shell, has crashed. To deal with this, without logging off and on the computer, you have to end any existing sessions of Explorer and run a new one.

To end existing Explorer sessions hold down the Ctrl and Alt keys and press the Delete key. On some versions of Windows this will open up the 'Windows Security' dialog box, if so then press the 'Task Manager' button; on other versions you will be taken straight to the 'Task Manager' program.

To stop the Explorer shell, go to the 'Processes' page and look for 'explorer.exe'. You can sort the processes into alphabetical order by clicking on the Image Name heading. If you find an entry for 'explorer.exe', highlight it and click the End Process button and click Yes on the warning dialog. If you don't find an entry for it you can go straight to the next step.

To restart the Explorer shell, click on the 'File' menu in Task Manager and select 'New Task (Run...)'. This will open the Run dialog box, into which you can type 'explorer' and click OK. The Taskbar should now reappear.